body, html {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: linear-gradient(to bottom, #001D3D, #003566);
  color: white;
  font-family: 'Arial', sans-serif;
}

.container {
  position: relative;
  width: 100%;
  height: 100%;
}

.snow {
  position: absolute;
  width: 100%;
  height: 100%;
  background-image: url('snowflake.png');
  background-size: contain;
  background-repeat: repeat;
  animation: snowfall 10s linear infinite;
}

@keyframes snowfall {
  from {
    background-position: 0 0;
  }
  to {
    background-position: 0 100vh;
  }
}

.tree {
  position: absolute;
  bottom: 15%;
  left: 50%;
  transform: translateX(-50%);
  width: 500px;
  height: 1000px;
  background: linear-gradient(to bottom, green, darkgreen);
  clip-path: polygon(50% 0%, 0% 100%, 100% 100%);
}

.lights {
  position: absolute;
  width: 100%;
  height: 100%;
  background-image: radial-gradient(circle, yellow 5%, transparent 50%);
  background-size: 15px 15px;
  animation: twinkle 2s ease-in-out infinite;
}

@keyframes twinkle {
  50% {
    opacity: 0.5;
  }
}

.gifts {
  position: absolute;
  bottom: 5%;
  left: 50%;
  display: flex;
  transform: translateX(-50%);
  gap: 10px;
}

.gift {
  width: 80px;
  height: 80px;
  background: red;
  border: 2px solid white;
  position: relative;
}

.gift::before, .gift::after {
  content: '';
  position: absolute;
  background: white;
}

.gift1 {
  animation: bounce 1.5s infinite;
}

.gift2 {
  animation: bounce 2s infinite 0.5s;
}

.gift3 {
  animation: bounce 2.5s infinite 1s;
}

@keyframes bounce {
  0%, 100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-8px);
  }
}

.message {
  position: absolute;
  top: 10%;
  width: 100%;
  text-align: center;
  font-size: 1.5em;
  text-shadow: 0 0 20px white;
  animation: fadeIn 3s ease-in-out;
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

/* 响应式调整 */
@media (max-width: 768px) {
  .tree {
    width: 90px;
    height: 140px;
  }

  .gifts {
    gap: 8px;
  }

  .gift {
    width: 30px;
    height: 30px;
  }

  .message {
    font-size: 1.5em;
  }

  .lights {
    background-size: 12px 12px;
  }
}
